In many experiments and applications utilizing lasers, it is desired to know the output power of the laser and how this power varies with time while the experiment is being performed. This could best be accomplished by using an inline power meter which does not obstruct the beam, which does not remove from the laser beam an appreciable number of photons, and which directly reads out the power with a response time short enough to indicate fluctations of interest. Such a device has not previously existed because low energy laser beams do not produce large enough effects and high energy laser beams tend to be too destructive. However, for high energy pulse laser beams, sampling meters have been used where part of the beam is reflected to a meter which reads the power. An example of this type of monitor is that such as disclosed by Jenkins et al., U.S. Pat. No. 4,035,088 dated Apr. 7, 1981. In this device, several reflectors or beam splitters are used. These beam splitters must be extremely uniform or each must be calibrated separately and it must be hoped that the beam splitters do not degrade in use. Therefore, it can be clearly seen that a non-obstructing laser beam sampling meter which may be used with both high power lasers and relatively low power lasers while operating in either the cw or the relatively pulse modes is needed.
Accordingly, it is an object of this invention to provide a sampling device which samples a laser beam and measures the beam power without blocking or unduly perturbing the beam.
Another object of this invention is to provide a meter which accurately and reliably samples the beam energy at full power without effecting the beam characteristics for further use of the beam.
Still another object of this invention is to provide a unique meter which allows the total laser output to pass therethrough and be measured for its power and allow the laser output to still be utilized to do the work desired.
Still another object of this invention is to provide a non-obstructing laser beam sampling meter which is used in line with the laser beam, which does not appreciably effect the beam, and which can be used with both cw and pulsed lasers.
Other objects and advantages of this invention will be obvious to those skilled in this art.